链式输送机(2)

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Procedia Engineering 29 (2012) 2146 – 2150

2012 International Workshop on Information and Electronics Engineering (IWIEE) Design and Experimental Analyse of Low Noise Double-

Pitch Silent Chain for Conveyor

Xiaolun Liua , Wencheng Wangb*, Wei Sunb ,Tiansong Wub ,

Jiajun Liua

, Jianfang Liub

a Chain Transmission Institute, Jilin University, Changchun 130025, China

b College of Mechanical Science and Engineering, Jilin University, Changchun 130025, China

Abstract

In order to improve current problems of large noise of double-pitch roller chain for conveyors, and implement higher efficiency and accuracy, a new type of double pitch silent chain was proposed by the method of change some plates with Nano-structured metal mesh - polyurethane composite material. Tested the noise characteristics among the new type double-pitch silent chain, the double-pitch roller chain and the short-pitch silent chain for conveyor and analysed the results. The results show that this new type of chain could effectively increase the transmission speed, ease chordal action, reduce the impact between chian plates and the sprocket tooth, and noise reduction effect is obvious. And the design could improve the conveying conditions distinctly. Therefore, the design of double-pitch silent chain for conveyors has value of application.

2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Harbin University of Science and Technology

Keywords: Mechanical Design; Double-pitch silent chain for conveyor; Composite materials; Noise reduction; test and analyse 1 Introduction

Chain for conveyor is a kind of chain driving systems which are wildly used in machinery manufacturing, agricultural machinery, metallurgy and other fileds to transport parts, goods or materials. Corresponding author. Tel.:+86-0431-85094365

E-mail address:[email protected]*

1877-7058 2011 Published by Elsevier Ltd.

doi:10.1016/j.proeng.2012.01.277

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And the conveyor chains mainly include double-pitch roller chains for conveyor and short-pitch silent chains for conveyor [1, 2]. But in conveying process, great problems are existting, such as low transmission speed, serious chordal action, extra large noise, and bad wearness in the conveyors which use double-pitch roller chains [3].Although the use of short-pitch silent chains in the conveyors largely increases the transmission speed, the problem of large noise has been unimproved.

There are few of informations about silent chains except some national standards, production manuals or patents, from which we can get from the manufacturers at home and abroad. In recent years, as general researches on silent chains have being carried out by scholars from different countrys, various chains are invented and applied in machines [4, 5, 6].

This paper proposes a new type of double-pitch silent chain for conveyors with nano-structured metal mesh - polyurethane composite material.it not only has high transmission speed just like short-pitch silent chains for conveyor, but also has the weight per meter lighter 25% than short pitch silent chains for conveyor. Because of the substituting the new elastic chain plates with nano-structured metal mesh - polyurethane composite material for one or two rigid chain plates, it can largely absorb impact power produced among chain plates and driving sprocket teethes, and lower the noise effectively.

2 Structure Design

The new type of double-pitch silent chain for conveyor is composed of chain plate, guide plate, reinforcing plate and scroll joint.Its structure is shown in figure 1. The chain plate include rigid chain plates which are produced by Si60Mn 2 material and elastic chain plates which are made up of nano-structured metal mesh - polyurethane composite material. The wires layed the wire mesh use the material of low-carbon steel Cr20MnMo, and its diameter range from 0.1mm to 0.3mm, the size of the hole of wire

mesh is 0.2mm-3mm, and the number of layer of wire mesh is desided by the thickness of chain plate.

Fig 1 Structure schematic of the new type of double-pitch silent chain for conveyors

The regid chain plate has three teeth (structure shown in figuer 2).The inner flank of two outside teeth is involute,which make an effective inner flank angle between a line tangent to a inner flank of the link at 0.75P0 and vertical line intersecting the tangent line less or equal to 30°. And the outer flank of the two outside teeth is beeline which make an effective outer flank angle between the outer flank and an vertical line intersecting the outer flank less or equal to 36°.The two outside tooth meshes with the sprocket teeth and transmit power or movement. The middle tooth of the chain plate does not engage with sprocket and plays a role of decrease the wearness between the top toe of chain plate and the track. The

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elastic chain plate has a similar structure with rigid chain plate, and the different is that the flanks of two outside teeth are larger than the rigid ones’ with an extension of 0.2mm-0.5mm. Elastic chain plates are symmetrically arranged in even-numbered chain links, and the layout number is discided by the wideth of chain link. Reinforcing plates are lays at the both side of the chain link which also include the elastic chain plate to balance the tensile strength between adjacent chain links and

enhance its transmission power and its carrying capacity.

Fig.2 Structure schematic of rigid plate

Due to structure of the new type composite chain for conveyor, meshing process of chain and sprocket is that the elastic chain plates mesh firstly with the sprocket tooth, as the nano-structured metal mesh - polyurethane composite material had good elasticity and shock absorption, the rigid chain plates start meshing with the sprocket when the elastic chain plates were compressed to a certain extent. Because of transient meshing, impact of the chain and sprocket is buffered by the composite chain plates; the noise of the new type composite chain for conveyor is decreased.

3 Noise Test and Analyse

Noise feature is an important indicator for measuring the quarity of chains. As an alternative to the existing short-pitch silent chain for conveyors and double-pitch roller chain for conveyors, it is necessary for the new type composite chain for conveyors to compare their noise features through tests and analysis.

3.1 Test Equipment and Instrument

To test the noise generated by experimental chains, the closed force flow noise test bench with automatic speed regulation and automatic loading was independently designed and developed (structure schematic shown in Figure 3). And in order to reduce other agencies’ noise to impact results of chain drive noise test, the measures were taken as follows: there was fiberglass between the test-bed and its base, and double acoustic box to insulate noise, and glass wool roll in the box to absorb noise. Noise test equipment was a portable TES-1358 sound analyzer meter, using 1 / 3-octave analysis in real time.

Xiaolun Liu et al. / Procedia Engineering 29 (2012) 2146 – 21502149

Experimental subject was the new type composite chain for conveyor, double-pitch roller chain for conveyor and short-pitch silent chain for conveyor, and all the three kind of chains have the same specification. Parameters of tested chains contained pitch of new type chain is P1=12.75 mm, pitch of double-pitch roller chain is P2=25.4mm, pitch of short-pitch silent chian is P3=12.7mm, chain link number N 1=N2=64, N3=128, driving sprocket tooth number Z1=39, driven sprocket tooth number Z2=40, working tension at tight side of chains F =400N , oil stream lubrication, and all the metal plate of experimental

chains have the same material , heat treatment process and hardness distribution.

Fig.3 Schematic of closed force flow noise test bench

1-Motor 2,5,6,10-Sprocket 4,9-Chain 7-Auto-loader 3,8-Shaft

3.2 Test Results and Analysis

Measurements were made during speed change of driving sprocket from 100 r/min to 600r/min at an interval of 50r/min.Test location was at the meshing point of tight-side chain and driving sprocket [7,8]. The date was recorded and analyzed and got the relationship curves of noise change with speed change of

driving sprocket for experimentalchain is shown in figure 4.

Fig.4 Ｎoise test for three experimental chains with speed change of driving sprocket

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It could be found that the three curves in figure 4 had the same changing trend that the higher the speed, the higher the noise when rotate speed of the driving sprocket ranged from 100r/min to 400r/min, but the noise of the new type composite chain was lower than the others’ at the same rotate speeds all the time. But when the rotate speed ranged from 400r/min to 600r/min, the three type curve get the distinct difference----noise of the new type composite chain increased smoothly, while the other two experimental chain made a shapely increase. So it could be clearly seen that difference in noise level of the new type roller chain and the other three kinds of roller chains get larger and larger as the speed increases, and the maximum difference in noise level was 13dB. Therefore, the new type roller chain can get better noise reduction effect with the higher speed of driving sprocket.

4 Discussion and Conclusion

The research on the conveyor chains for noise reduction started from changing the structures or materials, and a low noise nano-structured metal mesh - polyurethane composite double-pitch silent chain for conveyor was designed. Because the new tpye chain’s elastic plate with good elasticity and shock absorption, it could transform the energy of impact noise into the hot energy of nano-structured metal mesh - polyurethane composite and reduce vibration and noise of chain drive to achieve the aim of noise reduction.

From the present study of chain noise characteristics and on correlating the results of objective and subjective evaluation, the following conclusions are made:

a. As sprocket speed increase, the noise of all experimental chains will increase, but the noise of new type chain for conveyor increase more slowly.

b. The noise generated by the tested new type chain for conveyor is much lower than the others, especially at high speed. And in driving sprocket speed of 600r/min, the difference in noise level is 4-13dB.

References

[1] Zheng Zhi-feng,Wang Yi-xing,Chai Bang-heng.Chain drive[M]. Beijing:Chain Machine Press, 1984

[2]MENG Fan-zhong. The meshing principle of silent chain[M].Beijing:Chain Machine Press, 2008

[3] John Wright. Standard Handbook of Chains:Chain for Power Transmission and Material Handing Second edition. American Chain Association;2006,p.267–289.

[4] WANG Shu-kun, MENG Fan-zhong, LI Qi-hai, SUN Shu-hong. Noise Testing and Analysis of Automotive Engine Timing Chain[J]. Acta Armamentarii, 2009,30 (6):759-763

[5] J. A. Calvo, V. Diaz, J.L. San Roman & M Ramirez, Controlling the timing chain noise in diesel engines,Int. J. Vehicle Noise & Vibration, Vol. 2, No.1, 2006,p 75-89.

[6] S. P. Liu, Alan M. Dent, James W. Thornton, Martin W. Trethewey, K. W. Wang, Sabih I. Hayek & F. H. K. Chen, Experimental Evaluation of Automotive Timing Chain Drive Impact Noise, SAE Paper 951239, 1995. p 33-42.

[7]Yang Zhigang, Zheng Zhifeng, He Wendi. The occurrence process of the noise of roller chain drives [J]. Mechanical Design, 1994, 11 (3): 22-24.

[8] Gabriella Cerrato Jay, Sound/Vibration Quality Engineering, Sound & Vibration, April 2007, p 16-25